“…Control of the perovskite crystal structure and the chemical composition ratio using organic cations from methylammonium (MA = CH 3 NH 3 + ), formamidinium [FA = CH 3 (NH 2 ) 2 + ] [1,2], cesium (Cs) [3], guanidinium [4], divalent metals (lead, tin and bismuth) [5] and halogen anions (Cl − , Br − , and I − ) [6, 7, 8] is important factor for optimizing with tuning the photovoltaic and optical properties. The effects of halogen using bromide, iodide and chloride halides, amino cations, and hole-transporting layers on photovoltaic and optical properties were examined [4, 9, 10, 11].…”